In Japanese Patent Laid-open No. 2004-138062 there is described a high-pressure fuel pump having a relief valve device, the relief valve device comprising a valve seat member having a central fuel path and a seat surface formed around the central fuel path, a valve body serving as a pressure relief valve for being placed against the seat surface, and a spring member for pushing the valve body against the seat surface, the relief valve device being mounted to a body of the pump in such a manner that the spring member is positioned on the pressurizing chamber side.
Japanese Patent No. 4415929 discloses a high-pressure fuel pump in which a valve seat is provided at an inlet, on the pressurizing chamber-side, of a path connecting the pressurizing chamber with the high pressure path, a pressure relieve valve is installed on the pressurizing chamber-side of the valve seat, and there is provided, on the side of the high pressure path, a spring mechanism for producing the pressing force so that the relief valve is pressed toward the valve seat.